This invention relates to the construction for a heddle frame which includes top and bottom frame slats, each of which has a heddle rod integral therewith, or attached thereto, which supports heddles in the frame. The heddles include central thread eyes in which the individual warp yarn ends are held during shedding operations on the loom. The heddles are typically constructed of metal and are attached to the heddle rod by means of U-shaped slots in which the heddle rod is received.
The majority of the high-speed weaving machines, in use presently in the textile industry, provides for a 12 mm. space for each harness frame. Each frame in the set of frames is actuated by levers and cams all in side by side relationship. One or more of fixed nose guides on each frame, having a thickness essentially equal to the 12 mm. pitch between the center lines of the frames, serve to keep the thinner (generally 9 mm.) harness slats from clashing together.
Manufacturers of high-speed weaving machines recognize that the stroke of the shed opening could be reduced and the weaving machine speed increased if the pitch of the harness frames could be reduced to 10 mm. or less. Unfortunately, the currently popular asymmetrical riveted rod construction is not practical from clearance and strength standpoints when all dimensions of the slats are simply reduced.
A typical slat in use currently is shown in U.S. Pat. No. 4,633,916, issued Jan. 6, 1987 to John L. Rast and owned by the assignee of the present application. The slat disclosed in this patent greatly reduced the weight of the heddle frames and thereby led to increases in the weaving machine speeds because of the reduced weight. However, the problem arises that the asymmetrical slat disclosed in this patent still requires a greater pitch due to clearance and strength limitations, than a symmetrical slat according to the present invention.
Accordingly, an important object of the present invention is to provide a heddle frame assembly having a heddle slat which can be reduced in thickness without weakening the structure of the frame.
It is another object of the invention to provide a heddle frame slat which has a heddle support bar that is symmetrical.
It is still another important object of the invention to provide a heddle with symmetrical U-shaped open ends for engaging the heddle bar and avoiding accidental disengagement therefrom.